The present invention generally relates to internal gear pumps.
One of such internal gear pumps is disclosed for example in the German patent document DE 28 08 731 C2. This internal gear pump has a housing, in which a toothed ring provided with internal teeth is supported by a bearing ring rotatably about an axis. Moreover, it has a toothed pinion which is provided with outer teeth and engages with the toothed ring, and also turnably supported about an axis. The rotary axis of the toothed pinion is offset relative to the rotary axis of the toothed ring. The toothed ring or the toothed pinion is driven rotatably. A certain gap is required between the toothed pinion and the toothed ring in a radial direction relative to the rotary axes of the toothed pinion and the toothed ring, for avoiding clamping. On the other hand, this radial gap must be not too large, since thereby between the toothed pinion and the toothed gear gaps are produced from which the medium to be supplied by the internal gear pump passes, and therefore the efficiency of the internal gear pump can be worsened. For producing the internal gear pump, narrow tolerances of various components are prescribed, to hold the radial gap within a predetermined region. This leads to an expensive and complicated manufacture and mounting of the internal gear pump.
Accordingly, it is an object of the present invention to provide an internal gear pump of the above mentioned type, which avoids the disadvantages of the prior art.
In keeping with these objects and with others which will become apparent hereinafter, one feature of present invention resides, briefly stated, in an internal gear pump in which an adjusting device is associated with the bearing ring, so as to move the bearing ring in a radial direction relative to the rotary axis of the toothed ring in the housing to provide an adjustment and to block in a predetermined position.
When the internal gear pump is designed in accordance with the present invention the adjusting device provides an adjustment of the radial gap between the toothed gear and the toothed pinion. This makes possible the manufacture of the internal gear pump with greater tolerances and thereby reduced costs.
In accordance with another feature of the present invention, the adjusting device has an adjusting element which is displaceably guided in the housing in a radial direction and is connected with the bearing ring, and a fixing element which is accessible from the outer side of the housing and connected with the housing engages the adjusting element to displace the adjusting element in a radial direction and to block it in the adjusted position. This provides a simple design of the adjusting device.
In accordance with another feature of the present invention the adjusting element has a recess in which the fixing element engages transversely to the radial direction, the fixing element abuts against a side surface of the recess which faces radially the rotary axis of the toothed ring or faces away from it, the fixing element is connected movably with the housing in direction of its longitudinal axis and the side surface of the recess is inclined to the longitudinal surface of the fixing element, so that by moving the fixing element in direction of its longitudinal axis over the inclined side surface, the recess performs a movement of the adjusting element in the radial direction. This also simplifies the adjusting device.
In accordance with another feature of the present invention, the fixing element is formed as an adjusting screw which is screwed in a threaded opening in the housing, and during a rotary movement performs an adjusting movement in direction of its longitudinal axis. This provides a simple construction of the fixing element.
Finally, in accordance with another advantageous feature of the present invention, the bearing ring is supported via at least one elastic ring which is clamped between its outer surface and the housing, to produce a restoring force on the bearing ring which acts opposite to the adjusting force produced by the adjusting device on the bearing ring.
The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.